1. Field of the Invention
The present invention relates generally to eye testers and, more particularly, to a brightness acuity tester to assess functional visual acuity in bright light conditions and to test for recovery of visual acuity after photostressing the retina.
2. The Prior Art
Clinical practicioners have long been aware of the disparity occurring between outdoor functional vision in bright light conditions and that measured in a standard dark refracting lane. Significant disparities usually occur with ocular media opacities, including corneal scars, lenticular opacities happening in anterior subcapsular, posterior subcapsular and nuclear sclerotic cataracts, posterior capsular opacification following cataract surgery, and vitreous opacities including a dense central floater or asteroid hyalosis. As for photostressing the retina, patients with maculopathies, such as cystoid macular edema, central serous choroidopathy and senile macular degeneration evince markedly prolonged recovery from photostress.
Presently, only inaccurate methods are available to the practicioner for testing a patient's visual acuity in bright light conditions and for photostressing the retina to test for subsequent recovery of visual acuity. These present day methods include: taking the patient outside into bright sunlight or at least adjacent an undraped window exposed to bright sunlight; holding a light source, such as a penlight, adjacent the patient's eye; or placing a bright light source near a test chart. None of these methods is accurate, repeatable or employs consistent brightness or is particularly desirable. They are used simply for want of a better system.